Expandable vertebral body replacement system and method

ABSTRACT

Vertebral body replacement apparatuses, systems, and methods are provided. In various examples, an implantable device is configured to be inserted between a first vertebral body and a second vertebral body. The implantable device includes a first endplate configured to contact a superior endplate of the first vertebral body. A central member is pivotably coupled to the first endplate. A second endplate is configured to contact an inferior endplate of the second vertebral body. The implantable device includes a first insertion configuration and a second load-bearing configuration. The first insertion configuration includes the central member at a first angular position with respect to the first endplate. The second load-bearing configuration includes the central member at a second angular position with respect to the first endplate and the second endplate in a load-bearing position.

CLAIM OF PRIORITY

Benefit of priority is hereby claimed to U.S. Provisional PatentApplication Ser. No. 61/139,937, filed Dec. 22, 2008, which applicationis incorporated herein by reference.

TECHNICAL FIELD

This patent document pertains generally to orthopedics. Moreparticularly, but not by way of limitation, this patent documentpertains to a system, apparatus, and method for vertebral bodyreplacement for the spine using low insertion-profile implants.

BACKGROUND

Vertebral body replacement devices, or corpectomy implants, areindicated to provide anterior column support following a corpectomy,vertebrectomy, or spondylectomy as a result of trauma to the spine,removal of tumor material from the spinal column, or to correct spinaldeformity. Surgeons may utilize a number of different devices to providethis anterior column support, including structural bone struts made fromauto- or allograft tissue, structural titanium mesh cages, andexpandable titanium devices. The majority of these devices are designedto be introduced through a direct anterior, anterolateral, or directlateral approach channel that is perpendicular to the spinal column,with the implant itself oriented parallel with the axis of the spine.However, in cases where it is desirable to address the patient'spathology from a posterior or posterolateral approach, the patient'sneurological structures, including the spinal cord, cauda equina, andexiting nerve roots, limit the available access to the corpectomydefect, limiting the use of many of the currently known devices, orforcing the surgeon to use an implant size or configuration that is lessthan optimal.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like numerals describe similar components throughoutthe several views. Like numerals having different letter suffixesrepresent different instances of similar components. The drawingsillustrate generally, by way of example, but not by way of limitation,various embodiments discussed in the present document.

FIG. 1 illustrates a front perspective view of a low insertion profilevertebral body replacement implant in accordance with an example of thepresent invention in an expanded, load-bearing configuration;

FIG. 2 illustrates a front perspective view of the implant of FIG. 1 ina non-expanded insertion profile coupled to an insertion instrument;

FIG. 3 is a magnified front perspective view of the implant andinstrument of FIG. 2;

FIG. 4 illustrates a front perspective view of the implant andinstrument of FIG. 2 in which the implant is in a state between theinsertion configuration and the load-bearing configuration;

FIG. 5 is a magnified front perspective view of the implant andinstrument of FIG. 4;

FIG. 6 illustrates a front perspective view of the implant andinstrument of FIG. 2 in which the implant is in a load-bearingconfiguration;

FIG. 7 is a magnified front perspective view of the implant andinstrument of FIG. 6;

FIG. 8 illustrates a front perspective view of the implant andinstrument of FIG. 2 in which the implant is in a load-bearingconfiguration and a superior endplate is coupled to the implant;

FIG. 9 is a magnified front perspective view of the implant andinstrument of FIG. 8;

FIG. 10 illustrates a front perspective view of the implant andinstrument of FIG. 2 in which the implant is in an assembled andload-bearing configuration and the superior endplate-inserter portion ofthe instrument is uncoupled from the superior endplate;

FIG. 11 is a magnified front perspective view of the implant andinstrument of FIG. 10;

FIG. 12 illustrates a front perspective view of the implant andinstrument of FIG. 2 in which the implant is in an assembled,load-bearing, and expanded configuration;

FIG. 13 is a magnified front perspective view of the implant andinstrument of FIG. 12;

FIG. 14 is a perspective view of an example of an expansion mechanism ofthe implant of FIG. 1;

FIG. 15 is a side perspective view of an example insertion instrumentcoupled to the implant of FIG. 1;

FIGS. 16A-D are elevational views of a low insertion profile vertebralbody replacement implant in accordance with an example of the presentinvention; and

FIGS. 17A-C are elevational views of a low insertion profile vertebralbody replacement implant in accordance with an example of the presentinvention.

DETAILED DESCRIPTION

Certain terminology is used in the following description for convenienceonly and is not limiting. The words “right”, “left”, “lower”, and“upper” designate directions in the drawings to which reference is made.The words “inwardly” or “distally” and “outwardly” or “proximally” referto directions toward and away from, respectively, the geometric centerof the low insertion profile vertebral body replacement implant, relatedinstruments and related parts thereof. The words, “anterior”,“posterior”, “superior,” “inferior” and related words and/or phrasesdesignate preferred positions and orientations in the human body towhich reference is made and are not meant to be limiting. Theterminology includes the above-listed words, derivatives thereof andwords of similar import.

The present inventor has recognized, among other things, that limitedaccess to a corpectomy defect from a posterior or posterolateralapproach presents problems during vertebral body replacement surgicalprocedures. The present inventor has further recognized that thereexists an unmet need for a corpectomy implant configured for posterioror posterolateral approach that can be introduced in a minimallyinvasive, tissue-sparing manner, and provide stable structural support.

This patent document describes, among other things, apparatuses,systems, and methods for vertebral body replacement for the spine usinglow insertion-profile implants. In various examples, an implantabledevice is configured to be inserted between a first vertebral body and asecond vertebral body. The implantable device includes a first endplateconfigured to contact a superior endplate of the first vertebral body. Acentral member is pivotably coupled to the first endplate. A secondendplate is configured to contact an inferior endplate of the secondvertebral body. The implantable device includes a first insertionconfiguration and a second load-bearing configuration. The firstinsertion configuration includes the central member at a first angularposition with respect to the first endplate. The second load-bearingconfiguration includes the central member at a second angular positionwith respect to the first endplate and the central member engaged withthe second endplate.

In Example 1, a system includes an implantable device configured to beinserted between a first vertebral body and a second vertebral body. Theimplantable device includes a first endplate having a superior surfaceand an inferior surface. The inferior surface is configured to contact asuperior endplate of the first vertebral body. A central member ispivotably coupled to the first endplate. The central member includes afirst coupling feature. A second endplate has a superior surface and aninferior surface. The superior surface is configured to contact aninferior endplate of the second vertebral body. The second endplateincludes a second coupling feature configured to engage with the firstcoupling feature of the central member. The implantable device includesa first insertion configuration and a second load-bearing configuration.An insertion instrument is removably couplable to the implantabledevice. The insertion instrument is configured to advance theimplantable device in the first insertion configuration in between thesuperior endplate of the first vertebral body and the inferior endplateof the second vertebral body. The insertion instrument is actuatable toplace the implantable device in the second load-bearing configurationwith the central member pivoted with respect to the first endplate andthe second endplate moved with respect to the central column into aload-bearing position with the first coupling feature of the centralmember engaged with the second coupling feature of the second endplate.

In Example 2, the system of Example 1 optionally is configured such thatthe central member is pivotable through substantially ninety degreeswith respect to the first endplate.

In Example 3, the system of one or more of Examples 1-2 optionally isconfigured such that the second coupling feature is configured toslidingly engage with the first coupling feature of the central member.

In Example 4, the system of one or more of Examples 1-3 optionally isconfigured such that the second coupling feature of the second endplateis pivotably engaged with the first coupling feature of the centralmember.

In Example 5, the system of one or more of Examples 1-4 optionally isconfigured such that a height of the implantable device in the firstinsertion configuration is less than a height of the implantable devicein the second load-bearing configuration.

In Example 6, the system of one or more of Examples 1-5 optionally isconfigured such that the central member is pivotably coupled proximate aproximal side of the superior surface of the first endplate.

In Example 7, the system of one or more of Examples 1-6 optionally isconfigured such that the central member includes an inner strut memberand an outer strut member. The inner strut member is telescopicallymovable with respect to the outer strut member.

In Example 8, the system of Example 7 optionally comprises an expansionmechanism configured to telescopically move the inner strut member withrespect to the outer strut member.

In Example 9, the system of Example 8 optionally is configured such thatthe expansion mechanism includes a rack and pinion.

In Example 10, the system of one or more of Examples 1-9 optionally isconfigured such that the insertion instrument is couplable to the secondendplate. The insertion instrument is configured to slidingly advancethe second endplate into engagement with the first coupling feature ofthe central member.

In Example 11, the system of one or more of Examples 1-10 optionally isconfigured such that the central member includes at least first andsecond pivoting segments. The first pivoting segment is pivotable withrespect to the first endplate. The second pivoting segment is pivotablewith respect to the first pivoting segment.

In Example 12, the system of one or more of Examples 1-11 optionally isconfigured such that the central member is lockable in a pivotedposition. The central member is in the pivoted position with theimplantable device in the second load-bearing configuration.

In Example 13, the system of one or more of Examples 1-12 optionally isconfigured such that the insertion instrument includes a first slidingarm and a second sliding arm. The second sliding arm is configured toslide to pivot the central member with respect to the first endplate.The first sliding arm is configured to slide to engage the firstcoupling feature of the central member with the second coupling featureof the second endplate.

In Example 14, the system of Example 13 optionally is configured suchthat the insertion instrument includes a third sliding arm. The secondsliding arm is slidable with respect to the third sliding arm to pivotthe central member with respect to the first endplate. The first slidingarm is slidable with respect to the second sliding arm to engage thefirst coupling feature of the central member with the second couplingfeature of the second endplate.

In Example 15, an implantable device is configured to be insertedbetween a first vertebral body and a second vertebral body. Theimplantable device comprises a first endplate having a superior surfaceand an inferior surface. The inferior surface is configured to contact asuperior endplate of the first vertebral body. A central member ispivotably coupled to the first endplate. The central member includes afirst coupling feature. A second endplate has a superior surface and aninferior surface. The superior surface is configured to contact aninferior endplate of the second vertebral body. The second endplateincludes a second coupling feature configured to engage with the firstcoupling feature of the central member. The implantable device includesa first insertion configuration and a second load-bearing configuration.The first insertion configuration includes the central member at a firstangular position with respect to the first endplate. The secondload-bearing configuration includes the central member at a secondangular position with respect to the first endplate and the secondendplate in a load-bearing position with the first coupling feature ofthe central member engaged with the second coupling feature of thesecond endplate.

In Example 16, the implantable device of Example 15 optionally isconfigured such that the central member is pivotable from the firstangular position through substantially ninety degrees with respect tothe first endplate to the second angular position.

In Example 17, the implantable device of one or more of Examples 15-16optionally is configured such that the second coupling feature of thesecond endplate is configured to slidingly engage with the firstcoupling feature of the central member.

In Example 18, the implantable device of one or more of Examples 15-17optionally is configured such that the second coupling feature of thesecond endplate is pivotably engaged with the first coupling feature ofthe central member.

In Example 19, the implantable device of one or more of Examples 15-18optionally is configured such that a height of the implantable device inthe first insertion configuration is less than a height of theimplantable device in the second load-bearing configuration.

In Example 20, the implantable device of one or more of Examples 15-19optionally is configured such that the central member includes an innerstrut member and an outer strut member. The inner strut member istelescopically movable with respect to the outer strut member.

In Example 21, the implantable device of one or more of Examples 15-20optionally comprises an expansion mechanism configured to telescopicallymove the inner strut member with respect to the outer strut member.

In Example 22, the implantable device of one or more of Examples 15-21optionally is configured such that the central member includes at leastfirst and second pivoting segments. The first pivoting segment ispivotable with respect to the first endplate. The second pivotingsegment is pivotable with respect to the first pivoting segment.

In Example 23, the implantable device of one or more of Examples 15-22optionally is configured such that the central member is lockable in thesecond angular position. The central member is in the second angularposition with the implantable device in the second load-bearingconfiguration.

In Example 24, the implantable device of one or more of Examples 15-23optionally is configured such that the implantable device is configuredto detachably engage with an insertion instrument. The insertioninstrument is configured to advance the implantable device in the firstinsertion configuration in between the superior endplate of the firstvertebral body and the inferior endplate of the second vertebral body.The insertion instrument is actuatable to place the implantable devicein the second load-bearing configuration.

In Example 25, a method comprises placing an implantable device, in afirst insertion configuration, between a first vertebral body and asecond vertebral body using an insertion device. The implantable deviceis removably coupled to the insertion device. A central member of theimplantable device is pivoted from a first angular position with respectto a first endplate of the implantable device to a second angularposition with respect to the first endplate. A second endplate of theimplantable device is moved into a load-bearing position at an end ofthe central member to place the implantable device in a secondload-bearing configuration.

In Example 26, the method of Example 25 optionally is configured suchthat pivoting the central member includes pivoting the central membersubstantially ninety degrees.

In Example 27, the method of one or more of Examples 25-26 optionally isconfigured such that pivoting the central member includes actuating theinsertion instrument to pivot the central member.

In Example 28, the method of Example 27 optionally is configured suchthat actuating the insertion instrument includes sliding one sliding armof the insertion instrument with respect to another sliding arm of theinsertion instrument.

In Example 29, the method of one or more of Examples 25-28 optionally isconfigured such that moving the second endplate includes actuating theinsertion instrument to move the second endplate into engagement withthe central member.

In Example 30, the method of Example 29 optionally is configured suchthat actuating the insertion instrument includes sliding one sliding armof the insertion instrument with respect to another sliding arm of theinsertion instrument.

In Example 31, the method of one or more of Examples 25-30 optionally isconfigured such that moving the second endplate includes pivoting thesecond endplate with respect to the central member.

In Example 32, the method of one or more of Examples 25-31 optionallycomprises removing the insertion instrument from engagement with theimplantable device.

In Example 33, the method of one or more of Examples 25-32 optionally isconfigured such that pivoting the central member includes locking thecentral member in the second angular position.

In Example 34, the method of one or more of Examples 25-33 optionallycomprises expanding the implantable device to increase a height of theimplantable device.

In Example 35, the method of Example 34 optionally is configured suchthat expanding the implantable device includes actuating an expansionmechanism to telescopically move an inner strut member of the centralmember with an outer strut member of the central member.

Referring to FIGS. 1-15, in an example, a low insertion-profilevertebral body replacement (VBR) implant 100 and an associated insertioninstrument 200 are provided. The implant 100 includes a superior end, aninferior end, and a longitudinal axis therebetween. The implant 100further includes a proximal end engageable with the instrument 200 and adistal end opposite the proximal end. The implant 100 includes asuperior endplate 110 that is couplable with a central column 120 andthe central column 120 further includes an inner strut member 130 and anouter strut member 140. In an example, the inner strut member 130 isdisposed in the interior of the outer strut member 140. The superiorendplate 110 is, in an example, slidably lockable to the top surface ofthe inner strut member 130 via the inclusion of, for example, a dovetailand accommodating groove. The superior endplate 110 further includes aproximally disposed superior endplate instrument engagement feature 112.In another example, the superior endplate 110 is pivotably coupled tothe central column 120 such that the superior endplate 110 is pivotableinto place during insertion of the implant 100. In a further example,the superior endplate 110 includes a locking or engaging feature tomaintain the superior endplate 110 in place on the central column 120once the superior endplate 110 is pivoted into place.

The inner strut member 130 and the outer strut member 140 aretelescopically expandable in height with respect to one another toprovide a low insertion height/profile and permit expansion into a finalexpanded configuration between vertebral bodies. In various examples,the inner strut member 130 is translatable with respect to the outerstrut member 140 to thereby provide height expansion to the centralcolumn 120 via the inclusion of an expansion mechanism 122. In variousexamples, the expansion mechanism 122 includes a ratcheting expansionmechanism, a threaded expansion mechanism, a rack and pinion expansionmechanism, a stacking shim expansion mechanism, or other expansionmechanism. In the example shown in FIG. 14, the expansion mechanism 122includes a pinion 124 operatively coupled to and selectively actuatedusing the insertion instrument 200. The pinion 124 is positionable inengagement with a rack 126 within the inner strut member 130. Actuationof the pinion 124 translates the rack 126 with respect to the pinion 124and, in turn, telescopically translate the inner strut member 130 withrespect to the outer strut member 140. In this way, the expansionmechanism 122 is used to selectively expand the height of the centralcolumn 120. In some examples, the expansion mechanism 122 includes apawl or other feature to inhibit reverse movement of the inner strutmember 130 with respect to the outer strut member 140 to inhibit theexpanded central column 120 from retracting.

The inner strut member 130 and the outer strut member 140 may be openended, such that each assumes a C-shape in cross section. Alternatively,the inner strut member 130 and the outer strut member 140 may take-onhollow cylindrical or other tubular forms. In an example, an inferiorendplate 150 is couplable to the inferior proximal end of the outerstrut member 140 via a claw-like first outer strut hinge coupling 146and a claw-like second outer strut hinge coupling 147 that combine witha pin-like feature or a pair of pin-like features (not shown) on theinferior endplate 150 to form an inferior endplate hinge 154 thatenables the central column 120 to rotate with respect to the inferiorendplate 150 between an insertion configuration and a load bearingconfiguration. In an example, the central column 120 rotates throughapproximately ninety degrees with respect to the inferior endplate 150between the insertion configuration and the load bearing configuration.In other examples, the central column 120 rotates through greater thanor less than ninety degrees with respect to the inferior endplate 150between the insertion configuration and the load bearing configuration,depending upon various factors including, for instance, the location forthe implant 100 relative to the access channel, or the angularorientation of the final configuration of the implant 100 with respectto the access channel. The height of the implant 100 in the load-bearingconfiguration is greater than the height of the implant 100 in theinsertion configuration. A variety of other mechanisms can be utilizedto form the inferior endplate hinge 154 in addition to the claw-likefirst and second outer strut hinge couplings 146, 147 and thepin-feature on the inferior endplate 150. In an example, the centralcolumn can include two or more segments pivotably coupled to oneanother, such that a first segment is pivotably coupled to the inferiorendplate 150 and a second segment is pivotably coupled to the firstsegment and so on. In this way, the first segment can be pivoted intoplace with respect to the inferior endplate 150 and then each additionalsegment can be pivoted into place in series thereafter to erect thecentral column. In an example, the length of each segment of the centralcolumn can be selected and determined by the amount of access spaceavailable. In various examples, the two or more segments are eachlockable into place.

In an example, the outer strut member 140 includes a first outer strutinstrument engagement feature 141 and a second outer strut instrumentengagement feature (not shown) disposed on opposite distal superior endsof the outer strut member 140 in its load-bearing configuration. Theouter strut member 140 further includes a third outer strut instrumentengagement feature 143 and a fourth outer strut instrument engagementfeature 144 disposed on opposite proximal superior ends of the outerstrut member 140 in its load-bearing configuration. The inferior distalsurface of the outer strut member 140 further includes an optional firstsnap lock feature 145 that is configured to mate with a correspondingoptional second snap-lock feature 155 on the superior surface of theinferior endplate 150 to retain the central column 120 securely withrespect to the inferior endplate 150 in the load bearing configuration.The inferior endplate 150 further includes a proximally disposedinferior endplate engagement feature 152.

In an example, the superior surface of the superior endplate 110 isconfigured to contact the inferior endplate of a superior vertebral bodyand the inferior surface of the inferior endplate 150 is configured tocontact the superior endplate of an inferior vertebral body. Thesuperior and inferior endplates 110, 150 may include teeth, serrations,ridges, or other anti-repulsion features to secure the endplates 110,150 to the vertebral bodies in the implanted position. The superior andinferior endplates 110, 150 may be formed in a variety of modulargeometries, including circular, ovular, kidney bean-shaped, etc., toconform ideally to the endplates of the adjacent vertebral bodies. Thesuperior and inferior endplates 110, 150 may further be flat, tapered,concave, or convex to further accommodate the anatomy of the adjacentvertebral endplates. The superior and inferior endplates 110, 150 mayfurther include brachytherapy seeds for treating tumors or may be coatedor surface treated with beneficial agents. The superior and inferiorendplates 110, 150 may formed from rigid biocompatible material, such astitanium, stainless steel, or polymers such as PEEK. Alternately, thesuperior and inferior endplates 110, 150 can be formed from semi-rigidmaterial to enable the superior and inferior endplates 110, 150 toconform to the anatomy of the adjacent vertebral endplates via aforce-fit in the implanted position.

Disposed through the center of the implant 100 along the longitudinalaxis is an optional axial bore 160 configured to house graft material orallow boney through-growth to enable fusion to occur through the implant100.

In various examples, the insertion instrument 200 includes a proximalend and a distal end and a longitudinal axis extending therebetween. Insome examples, the instrument 200 includes a first sliding arm 210, asecond sliding arm 220, and a third sliding arm 230, wherein the firstand second sliding arms 210, 220 are slidably translatable with respectto one another along the longitudinal axis and the second and thirdsliding arms 220, 230 are slidably translatable with respect to oneanother along the longitudinal axis. The first sliding arm 210 includesa distally disposed engagement feature (not shown) that is couplable tothe superior endplate engagement feature 112. The second sliding arm 220includes a distally disposed first forked grasping member 221 that ishingedly coupled to the second sliding arm 220 via a second sliding armhinge 222. The first forked grasping member 221 further includes a firstfork arm 223 and a second fork arm 224, wherein the first fork arm 223and the second fork arm 224 each include protrusions or other features(not shown) that are hingedly mateable with the first outer strutinstrument engagement feature 141 and the second outer strut instrumentengagement feature (not shown), respectively, to form a first fork armhinge 225 and a second fork arm hinge 226, respectively. In an example,the third sliding arm 230 terminates distally in a non-hingedly coupledsecond forked grasping member 231. The second forked grasping member 231further includes a second fork first arm 233 and a second fork secondarm 234, wherein the second fork first arm 233 and the second forksecond arm 234 each include protrusions or other features (not shown)that are hingedly mateable with the third outer strut instrumentengagement feature 143 and the fourth outer strut instrument engagementfeature 144, respectively, to form a second fork first arm hinge 235 anda second fork second arm hinge (not shown), respectively. Disposedthrough the proximal ends of the second fork first arm 233 and thesecond fork second arm 234 is a second forked grasping member base hinge237 that hingedly couples to the base portion of an extending forkmember (not shown) that splits into an extending fork member first arm239 and an extending fork member second arm 240. The extending forkmember first arm 239 and the extending fork member second arm 240include protrusions or other features (not shown) that are hingedlymateable with the inferior endplate engagement feature 152 to form anextending fork member hinge 241. The extending fork member (not shown)may not include arms but, rather, can hingedly couple to the inferiorendplate engagement feature 152 in any of a variety of other ways aswould be apparent to one having ordinary skill in the art.

The example insertion instrument 200 shown in FIG. 15 includesdepictions of features, as described below, which are not shown in FIGS.2-13, although it is contemplated that such features can be used withthe insertion instrument 200 shown in FIGS. 2-13. In various examples,the insertion instrument 200 is used with a tunnel 250. The tunnel 250is configured to be inserted within an access channel and provides spacefor insertion of the implant 100 and for insertion, withdrawal, andoperation of the insertion instrument 200 while at the same timeproviding at least some protection of the body tissue in the area of theaccess channel from being scraped, pinched, or otherwise contacted bythe implant 100 and/or the insertion instrument 200. The insertioninstrument 200, in an example, includes a handle 260 and an actuator262. In an example, the handle 260 is shaped substantially like a pistolgrip and the actuator 262 is shaped substantially like a trigger. Theactuator 262 is coupled to the first and second sliding arms 210, 220 tomove the first and second sliding arms 210, 220, as described herein,during insertion of the implant 100. In an example, the insertioninstrument 200 includes a rod 270 disposed within a channel in theinsertion instrument 200 and coupled to the pinion 124 of the expansionmechanism 122. In an example, the pinion 124 is integrally attached tothe rod 270. In a further example, the pinion 124 forms a distal end ofthe rod 270. In each of these examples, rotation of the rod 270 at theproximal end of the insertion instrument 200 rotates the pinion 124 andactuates the expansion mechanism 122 to translate the inner strut member130 with respect to the outer strut member 140. In various examples, therod 270 can be the shaft of a separate tool, can include an engagementfeature to be matingly engaged with a separate tool, or can include agrip for manual rotation of the rod 270.

In operation, and in continuing reference to FIGS. 1-15, a surgeonprovides an access channel to the spine and a portion of a damaged ordiseased vertebral body in need of replacement is removed. The implant100, in the insertion configuration (FIGS. 1 and 2), is engaged to theinsertion instrument 200, as shown in FIGS. 2 and 3, by coupling thedistal portions of the first fork arm 223 and the second fork arm 224 tothe first outer strut instrument engagement feature 141 and the secondouter strut instrument engagement feature 142, respectively, and bycoupling the distal portions of the second fork first arm 233 and thesecond fork second arm 234 to the third outer strut instrumentengagement feature 143 and the fourth outer strut instrument engagementfeature 144, respectively, and by coupling the distal portions of theextending fork member first arm 239 and the extending fork second arm240 to the inferior endplate engagement feature 152. The implant 100, inthe insertion configuration, is then implanted into the space left bythe removed portion of the diseased or damaged vertebral body bymanipulating the instrument 200. Once the implant 100 is positioned withrespect to the remaining vertebral bodies, the instrument 200 ismanipulated to force the implant 100 into the load bearingconfiguration, as shown in FIGS. 4-7, by advancing the second slidingarm 220 distally with respect to the third sliding arm 230, therebycausing the second sliding arm hinge 222, the first fork arm hinge 225,the second fork arm hinge 226, the second fork first arm hinge 235, thesecond fork second arm hinge 236, the second forked grasping member basehinge 237, and the extending fork member hinge 241 to articulate andcause the central column 120 to rotate from the insertion configurationto the load bearing configuration and further cause the engagement ofthe first snap lock feature 145 with the second snap lock feature 155.As shown in FIGS. 6-9 and 15, the first sliding arm 210 is then coupledto the superior endplate 110 via the superior endplate engagementfeature 112 and the first sliding arm 210 is coupled to the secondsliding arm 220. The first sliding arm 210 and the distally coupledsuperior endplate 110 are advanced distally with respect to the secondsliding arm 220, causing the superior endplate 110 to engage and coupleto the superior surface of the inner strut member 130. The first slidingarm 210 is then advanced proximally with respect to the second slidingarm 220, thereby uncoupling the first sliding arm 210 from the superiorendplate 110, as shown in FIGS. 10 and 11. In another example, thesuperior endplate 110 is pivotably coupled to the central column 120 topivot into position with rotation of the central column 120 with respectto the inferior endplate 150, in a manner similar to that described inmore detail below. The implant 100 is then expanded to a desired height,as shown in FIGS. 12 and 14, by actuating the expansion mechanism 122.

A number of different methods are envisioned as suitable for impartingforce to the necessary elements to cause the inner strut member 130 toadvance with respect to the outer strut member 140, depending in partupon the expansion mechanism chosen to characterize the implant 100. Forexample, a distracting force can be imparted to the superior andinferior endplates 110, 150 or to the inner strut member 130 by theinsertion instrument 200 itself. Alternately, a separate simpleexpansion instrument can be coupled over the second and/or third slidingarms 220, 230 and impart the necessary force to the necessary elementsof the implant 100 to cause height expansion. In addition, the separatesimple expansion instrument can be coupled to the implant 100 after theinstrument 200 is disengaged from the implant 100. Once the desiredheight has been achieved, the instrument 200 is uncoupled from theimplant 100 and the access channel is sealed and the wound covered.

In an example, the implant 100 is not expandable in height via anexpansion mechanism, but, rather, is simply characterized by the lowprofile insertion configuration and the taller load bearingconfiguration. In such an arrangement, the desired height of the implantcan be tailored by choosing, in part, from a range of different superiorendplate heights. In another example, the desired height of the implantcan be tailored by choosing, in part, from a range of different strutmembers with varying heights.

It will be appreciated by those skilled in the art that changes could bemade to the examples described above without departing from the broadinventive concept thereof. For example, the inner and outer strutmembers 130, 140 may be fixed in orientation relative to the superiorand inferior endplates 110, 150 and expand longitudinally in a similarmanner to a car jack, as opposed to expanding pivotably andlongitudinally, as is described in various examples above. It isunderstood, therefore, that this invention is not limited to theparticular examples disclosed, but it is intended to cover modificationswithin the spirit and scope of the present invention as defined by thepresent description.

Referring now to FIGS. 16A-D, in another example, a lowinsertion-profile VBR implant 300 is shown. An associated insertiondevice, although not shown for ease of illustration, is used with theimplant 300 and is substantially similar to the insertion device 200described above. In an example, the insertion device used with theimplant 300 differs from the insertion device 200 described above inthat it lacks the structure required to slide the superior endplate intoposition, for reasons that should become apparent from the descriptionof the implant 300 below. It is noted that, in various examples, inaddition to the features and properties described below, the implant 300can include one or more features and/or one or more properties similarto those included with the implant examples discussed above.

The implant 300, in an example, includes an inferior endplate 350. Acentral column 320 is pivotably coupled to the inferior endplate 350. Inan example, the central column 320 includes an inner strut member 330telescopically coupled with an outer strut member 340. In a furtherexample, the inner strut member 330 is telescopically disposed withinthe outer strut member 340. As shown in FIG. 16D, the inner strut member330 and the outer strut member 340, in an example, are telescopicallyexpandable in height with respect to one another to provide a lowinsertion height/profile and permit expansion into a final expandedconfiguration between vertebral bodies. In various examples, the innerstrut member 330 is translatable with respect to the outer strut member340 to thereby provide height expansion to the central column 320 viathe inclusion of an expansion mechanism. In various examples, theexpansion mechanism includes a ratcheting expansion mechanism, athreaded expansion mechanism, a rack and pinion expansion mechanism, astacking shim expansion mechanism, or other expansion mechanism.

In the example shown in FIGS. 16A-D, the implant 300 includes a superiorendplate 310 pivotably engaged with the central column 320. In anexample, the inner strut member 330 includes a first snap lock feature335 that is configured to mate with a corresponding second snap-lockfeature on the inferior surface of the superior endplate 310 to retainthe superior endplate 310 securely in a load bearing configuration withrespect to the central column 320.

In operation, in an example, the implant 300 is inserted similarly tothe insertion of the implant 100 described above. However, the superiorendplate 310 pivots into place with the pivoting of the central column320. In an example, the insertion device is configured to pivot thesuperior endplate 310 into position. In another example, the superiorendplate 310 is pivoted into place with the pivoting of the centralcolumn 320 and sliding contact of the superior endplate 310 with aninferior endplate of a superior vertebral body against which thesuperior endplate 310 is intended to bear in the load bearingconfiguration.

Referring now to FIGS. 17A-C, in another example, a lowinsertion-profile VBR implant 400 is shown. An associated insertiondevice, although not shown for ease of illustration, is used with theimplant 400 and is substantially similar to the insertion device 200described above. It is noted that, in various examples, in addition tothe features and properties described below, the implant 400 can includeone or more features and/or one or more properties similar to thoseincluded with the implant examples discussed above.

The implant 400, in an example, includes an inferior endplate 450. Acentral column 420 is pivotably coupled to the inferior endplate 450. Inan example, the central column 420 includes two or more pivotingsegments. In the example shown in FIGS. 17A-C, the central column 420includes first, second, and third pivoting segments 440A, 440B, 440C,with the first pivoting segment 440A pivotably coupled to the inferiorendplate 450, the second pivoting segment 440B pivotably coupled to thefirst pivoting segment 440A, and the third pivoting segment 440Cpivotably coupled to the second pivoting segment 440B. The implant 400includes an inner strut member 430 telescopically coupled with the thirdpivoting segment 440C. In a further example, the inner strut member 430is telescopically disposed within the third pivoting segment 440C. Asshown in FIG. 17C, the inner strut member 430 and the third pivotingsegment 440C, in an example, are telescopically expandable in heightwith respect to one another to provide a low insertion height/profileand permit expansion into a final expanded configuration betweenvertebral bodies. In various examples, the inner strut member 430 istranslatable with respect to the third pivoting segment 440C to therebyprovide height expansion to the central column 420 via the inclusion ofan expansion mechanism. In various examples, the expansion mechanismincludes a ratcheting expansion mechanism, a threaded expansionmechanism, a rack and pinion expansion mechanism, a stacking shimexpansion mechanism, or other expansion mechanism. Although shown withthree pivotable segments 440A, 440B, 440C, in various examples, theimplant can include more or fewer than three segments, depending uponthe final desired height of the implant, the size of the access channel,etc. In some examples, the segments of the implant can be preassembled.In other examples, the segments of the implant can be assembled at thetime of surgery to enable customization of the implant, for instance,based on the location for the implant, the size and shape of the accesschannel, and various other conditions present at the time of surgery.

In the example shown in FIGS. 17A-C, the implant 400 includes a superiorendplate 410 slidably engageable with the central column 420 in a mannersimilar to that described above with respect to the implant 100. Inother examples, the superior endplate 410 is pivotably engaged with thecentral column 420 in a manner similar to that described above withrespect to the implant 300.

In operation, in an example, the implant 400 is inserted similarly tothe insertion of the implant 100 described above. However, in anexample, the associated insertion device is configured to pivot all ofthe segments of the central column 420 into a substantially alignedload-bearing position, as shown in FIG. 17C. Once the central column 420is pivoted into the load-bearing position and the superior endplate 410is slid or pivoted into position on the central column 420, theexpansion mechanism can be actuated to increase the height of thecentral column 420 to a desired final height to bear against an inferiorendplate of a superior vertebral body against which the superiorendplate 410 is intended to bear in the load bearing configuration.

The above Detailed Description includes references to the accompanyingdrawings, which form a part of the Detailed Description. The drawingsshow, by way of illustration, specific embodiments in which theinvention can be practiced. These embodiments are also referred toherein as “examples.” All publications, patents, and patent documentsreferred to in this document are incorporated by reference herein intheir entirety, as though individually incorporated by reference. In theevent of inconsistent usages between this document and those documentsso incorporated by reference, the usage in the incorporated reference(s)should be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In the appended claims, the terms “including” and“in which” are used as the plain-English equivalents of the respectiveterms “comprising” and “wherein.” Also, in the following claims, theterms “including” and “comprising” are open-ended, that is, a system,device, article, or process that includes elements in addition to thoselisted after such a term in a claim are still deemed to fall within thescope of that claim. Moreover, in the following claims, the terms“first,” “second,” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements on their objects.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or morefeatures thereof) may be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. Also, in the above DetailedDescription, various features may be grouped together to streamline thedisclosure. This should not be interpreted as intending that anunclaimed disclosed feature is essential to any claim. Rather, inventivesubject matter may lie in less than all features of a particulardisclosed embodiment. Thus, the following claims are hereby incorporatedinto the Detailed Description, with each claim standing on its own as aseparate embodiment. The scope of the invention should be determinedwith reference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

The Abstract is provided to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims.

1. A system comprising: an implantable device configured to be insertedbetween a first vertebral body and a second vertebral body, theimplantable device including: a first endplate having a superior surfaceand an inferior surface, the inferior surface configured to contact asuperior endplate of the first vertebral body; a central memberpivotably coupled to the first endplate, the central member including afirst coupling feature; and a second endplate having a superior surfaceand an inferior surface, the superior surface configured to contact aninferior endplate of the second vertebral body, the second endplateincluding a second coupling feature configured to engage with the firstcoupling feature of the central member, wherein the implantable deviceincludes a first insertion configuration and a second load-bearingconfiguration; and an insertion instrument removably couplable to theimplantable device, the insertion instrument configured to advance theimplantable device in the first insertion configuration in between thesuperior endplate of the first vertebral body and the inferior endplateof the second vertebral body, the insertion instrument being actuatableto place the implantable device in the second load-bearing configurationwith the central member pivoted with respect to the first endplate andthe second endplate to move with respect to the central column into aload-bearing position with the first coupling feature of the centralmember engaged with the second coupling feature of the second endplate.2. The system of claim 1, wherein the central member is pivotablethrough substantially ninety degrees with respect to the first endplate.3. The system of claim 1, wherein the second coupling feature isconfigured to slidingly engage with the first coupling feature of thecentral member.
 4. The system of claim 1, wherein the second couplingfeature of the second endplate is pivotably engaged with the firstcoupling feature of the central member.
 5. The system of claim 1,wherein a height of the implantable device in the first insertionconfiguration is less than a height of the implantable device in thesecond load-bearing configuration.
 6. The system of claim 1, wherein thecentral member is pivotably coupled proximate a proximal side of thesuperior surface of the first endplate.
 7. The system of claim 1,wherein the central member includes an inner strut member and an outerstrut member, the inner strut member being telescopically movable withrespect to the outer strut member.
 8. The system of claim 7, comprisingan expansion mechanism configured to telescopically move the inner strutmember with respect to the outer strut member.
 9. The system of claim 8,wherein the expansion mechanism includes a rack and pinion.
 10. Thesystem of claim 1, wherein the insertion instrument is couplable to thesecond endplate, the insertion instrument being configured to slidinglyadvance the second endplate into engagement with the first couplingfeature of the central member.
 11. The system of claim 1, wherein thecentral member includes at least first and second pivoting segments, thefirst pivoting segment being pivotable with respect to the firstendplate, and the second pivoting segment being pivotable with respectto the first pivoting segment.
 12. The system of claim 1, wherein thecentral member is lockable in a pivoted position, the central memberbeing in the pivoted position with the implantable device in the secondload-bearing configuration.
 13. The system of claim 1, wherein theinsertion instrument includes a first sliding arm and a second slidingarm, wherein the second sliding arm is configured to slide to pivot thecentral member with respect to the first endplate, and the first slidingarm is configured to slide to engage the first coupling feature of thecentral member with the second coupling feature of the second endplate.14. The system of claim 13, wherein the insertion instrument includes athird sliding arm, wherein the second sliding arm is slidable withrespect to the third sliding arm to pivot the central member withrespect to the first endplate, and the first sliding arm is slidablewith respect to the second sliding arm to engage the first couplingfeature of the central member with the second coupling feature of thesecond endplate.
 15. An implantable device configured to be insertedbetween a first vertebral body and a second vertebral body, theimplantable device comprising: a first endplate having a superiorsurface and an inferior surface, the inferior surface configured tocontact a superior endplate of the first vertebral body; a centralmember pivotably coupled to the first endplate, the central memberincluding a first coupling feature; and a second endplate having asuperior surface and an inferior surface, the superior surfaceconfigured to contact an inferior endplate of the second vertebral body,the second endplate including a second coupling feature configured toengage with the first coupling feature of the central member, whereinthe implantable device includes a first insertion configuration and asecond load-bearing configuration, the first insertion configurationincluding the central member at a first angular position with respect tothe first endplate, the second load-bearing configuration including thecentral member at a second angular position with respect to the firstendplate and the second endplate in a load-bearing position with thefirst coupling feature of the central member engaged with the secondcoupling feature of the second endplate.
 16. The implantable device ofclaim 15, wherein the central member is pivotable from the first angularposition through substantially ninety degrees with respect to the firstendplate to the second angular position.
 17. The implantable device ofclaim 15, wherein the second coupling feature of the second endplate isconfigured to slidingly engage with the first coupling feature of thecentral member.
 18. The implantable device of claim 15, wherein thesecond coupling feature of the second endplate is pivotably engaged withthe first coupling feature of the central member.
 19. The implantabledevice of claim 15, wherein a height of the implantable device in thefirst insertion configuration is less than a height of the implantabledevice in the second load-bearing configuration.
 20. The implantabledevice of claim 15, wherein the central member includes an inner strutmember and an outer strut member, the inner strut member beingtelescopically movable with respect to the outer strut member.
 21. Theimplantable device of claim 15, comprising an expansion mechanismconfigured to telescopically move the inner strut member with respect tothe outer strut member.
 22. The implantable device of claim 15, whereinthe central member includes at least first and second pivoting segments,the first pivoting segment being pivotable with respect to the firstendplate, and the second pivoting segment being pivotable with respectto the first pivoting segment.
 23. The implantable device of claim 15,wherein the central member is lockable in the second angular position,the central member being in the second angular position with theimplantable device in the second load-bearing configuration.
 24. Theimplantable device of claim 15, wherein the implantable device isconfigured to detachably engage with an insertion instrument, theinsertion instrument configured to advance the implantable device in thefirst insertion configuration in between the superior endplate of thefirst vertebral body and the inferior endplate of the second vertebralbody, the insertion instrument being actuatable to place the implantabledevice in the second load-bearing configuration.
 25. A methodcomprising: placing an implantable device, in a first insertionconfiguration, between a first vertebral body and a second vertebralbody using an insertion device, the implantable device being removablycoupled to the insertion device; pivoting a central member of theimplantable device from a first angular position with respect to a firstendplate of the implantable device to a second angular position withrespect to the first endplate; and moving a second endplate of theimplantable device into a load-bearing position at an end of the centralmember to place the implantable device in a second load-bearingconfiguration.
 26. The method of claim 25, wherein pivoting the centralmember includes pivoting the central member substantially ninetydegrees.
 27. The method of claim 25, wherein pivoting the central memberincludes actuating the insertion instrument to pivot the central member.28. The method of claim 27, wherein actuating the insertion instrumentincludes sliding one sliding arm of the insertion instrument withrespect to another sliding arm of the insertion instrument.
 29. Themethod of claim 25, wherein moving the second endplate includesactuating the insertion instrument to move the second endplate intoengagement with the central member.
 30. The method of claim 29, whereinactuating the insertion instrument includes sliding one sliding arm ofthe insertion instrument with respect to another sliding arm of theinsertion instrument.
 31. The method of claim 25, wherein moving thesecond endplate includes pivoting the second endplate with respect tothe central member.
 32. The method of claim 25, comprising removing theinsertion instrument from engagement with the implantable device. 33.The method of claim 25, wherein pivoting the central member includeslocking the central member in the second angular position.
 34. Themethod of claim 25, comprising expanding the implantable device toincrease a height of the implantable device.
 35. The method of claim 34,wherein expanding the implantable device includes actuating an expansionmechanism to telescopically move an inner strut member of the centralmember with an outer strut member of the central member.